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Homework Help: Charge on the ball

  1. Sep 10, 2005 #1
    Here is the problem word for word:

    A charged cork ball of mass 1.53g is suspended on a light string in the presense of a uniform electric field. When the electric field has an x-component of 346000 N/C and a y-component of 383000 N/C, the ball is in equilibrium at 37.6151 degrees. The acceleration of gravity is 9.8 m/s^2 and the Coulomb constant is 8.99X10^9 Nm^2/C^2. Find the charge on the ball.

    I know that E=F/q; therefore, after rearranging the formula you get q=F/E, which will give me the charge of the ball. When solving for the magnitude of the force on the ball, I get stuck. The picture of the problem shows E to be at an angle as suggested by x-component of 346000 N/C and a y-component of 383000 N/C, which suggests the field to be at 47.91 degrees. Should I even worry about the angle of the electrical field?

    I guess the fact that the problems states that the electric field has an x and y component is throwing me off. Anyone have any hints on how to get started in the right direction on this problem?
  2. jcsd
  3. Sep 10, 2005 #2
    Find the E field vector by doing the vector sum, then from there, you can just say that an E field of magnitude xxx N/C deflects a ball of mass 1.53g by 37.6151 degrees in the direction (or in the opposite direction if its negatively charged) of the field.
  4. Sep 10, 2005 #3
    That is exactly the help I was needing. I believe I can work the problem now. Thanks for the clarification.
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